If you can't refuse to go out and eat dinner with them, plan ahead. Many restaurants have menu's available online now, look yours up and look ahead for something on the healthier side to order. That way when you get there you don't even have to look at the menu and all those tempting options, you already know
Or you can work those kinds of nights into your calorie budget, just keep a low calorie count going without starving yourself and save most of them for dinner, I do this sometimes.
As for the scale thing, my digital scale hates being moved. It needs to be on a certain tile or its readings are different. I think the tiles in my bathroom are a little wonky and uneven. Just find a place it seems to work and leave it there, if it continues to pop up such random numbers think about changing the batteries (If you haven't already) you would be surprised at how off the scale can be when the batteries are dying. If all else fails then you can look into getting a new scale.